Hydrogen-terminated polycrystalline diamond MOSFETs with Al2O3 passivation layers grown by atomic layer deposition at different temperatures

• Main Authors: Zeyang Ren, Guansheng Yuan, Jinfeng Zhang, Lei Xu, Jincheng Zhang, Wanjiao Chen, Yue Hao
• Format: Article
• Language: English
• Published: AIP Publishing LLC 2018-06-01
• Series: AIP Advances
• Online Access: http://dx.doi.org/10.1063/1.5037925

Metal oxide semiconductor field effect transistors (MOSFETs) with Al2O3 passivation layer grown by atomic layer deposition (ALD) at 200 oC and 300 oC were fabricated on hydrogen-terminated polycrystalline diamond by using gold mask technology. The device with 200 oC grown Al2O3 dielectric shows high output current, low on-resistance, large threshold voltage and high transconductance compared to that with 300 oC grown Al2O3. A maximum drain current of 339 mA/mm has been achieved by the 2-μm device of the former kind, which, as we know, is the best result reported for the diamond MOSFETs with the same gate length except the NO2-adsorbed case. The current-voltage (I-V) of gate diodes of both kinds of devices show the gate forward leakage is dominated by the Frenkel-Poole (FP) emission mechanism at a high electric field, and the gate of the latter device can sustain higher forward bias. The stability of successive I-V measurements of both kinds of devices was proved. We expect that a high performance H-diamond MOSFET with high stability can be achieved by a double-layer dielectric structure with 200 oC grown Al2O3 stacked by another high-quality high κ dielectric.